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Embodying a virtual hand through coning brain stimulation and VR

Michela Bassolino, a SNSF Ambizione fellowship in Blanke’s Lab, and her team were able to induce the well-known rubber hand illusion in virtual reality, with non-invasive brain stimulation instead of direct physical stimulation to the body. Bassolino hopes that continuing this research will allow the team to uncover new features of embodiment in healthy participants and patients with body disorders.

Around 20 years ago, Botvinich and Cohen, two researchers from Pennsylvania, USA, discovered the now famous Rubber Hand Illusion (RHI), a powerful illusion in which tactile stimuli to the real participants’ hand coupled with synchronous visual stroking of a rubber hand induces the vivid sensation that the rubber hand is in fact the real one. Since then, the RHI has become a proxy to study multiple aspects of consciousness, embodiment and multisensory processing. A decade after this seminal work, Slater and colleagues managed to induce this illusion using a virtual hand instead of a rubber hand. This opened the door for inducing the RHI in virtual reality (VR).

Now, the work by Bassolino and colleagues pushes the limits of the RHI to a new level. With an innovative combination of VR and transcranial magnetic stimulation, the team consistently induced the perception that a virtual hand seen by participants was in fact their own. Researchers argue that illusory embodiment occurred due to the integration between TMS-induced activation of corticospinal tract and hand twitches with temporally matched visual feedback in VR.

This research, which represents the first time the RHI is achieved through non-invasive brain stimulation, is now published in the European Journal of Neuroscience. The New Scientist picked up on it, and in their piece (by Laura Olivieri Robles – New Yorker), Paul Marasco from the Cleveland Clinic in Ohio, USA, emphasizes the importance of this breakthrough: “our brains don’t seem to distinguish between real and fake inputs (…) they blurred the lines between what’s virtual and what’s human”. Digital Trends, a popular web journal about emerging digital technology and VR, has also written an article regarding the potential impacts of this new work.

Together with Olaf Blanke, Bassolino hopes that this work will provide a new method to reveal key insights in the study of embodiment in healthy participants and patients

The lab congratulates Michela and her colleagues for the amazing work, and wishes the best for the continuation of these efforts.